The present claimed invention relates to the field of flat panel displays. More specifically, the present claimed invention relates to a flat panel display and methods for forming a flat panel display having a seal formed using seal material.
A Cathode Ray Tube (CRT) display generally provides the best brightness, highest contrast, best color quality and largest viewing angle of prior art displays. CRT displays typically use a layer of phosphor that is deposited on a thin glass faceplate. These CRTs generate a picture by using one to three electron beams that generate electrons that are scanned across the phosphor in a raster pattern. The phosphor converts the electron energy into visible light so as to form the desired picture. However, prior art CRT displays are large and bulky due to the large vacuum tubes that enclose the cathode and extend from the cathode to the faceplate of the display. Therefore, typically, other types of display technologies such as active matrix liquid crystal display, plasma display and electroluminiscent display technologies have been used in the past to form thin displays.
Recently, a thin flat panel display has been developed that uses the same process for generating pictures as is used in CRT devices. These thin flat panel displays use a backplate including a matrix structure of rows and columns of electrodes. One such flat panel display is described in U.S. Pat. No. 5,541,473 titled GRID ADDRESSED FIELD EMISSION CATHODE that is incorporated herein by reference as background material. Typically, the backplate is formed by depositing a cathode structure (electron emitting) on a glass plate. The cathode structure includes emitters that generate electrons. The backplate typically has an active area within which the cathode structure is deposited. Typically, the active area does not cover the entire surface of the glass plate, leaving a thin strip that extends around the glass plate. Electrically conductive traces extend through the thin strip to allow for connectivity to the active area.
Prior art flat panel displays include a thin glass faceplate having one or more layers of phosphor deposited over the interior surface thereof. The faceplate is typically separated from the backplate by about 0.1 to 2 millimeters. The faceplate includes an active area within which the layer (or layers) of phosphor is deposited. A thin strip that does not contain phosphor extends from the active area to the edges of the glass plate. The faceplate is attached to the backplate using a glass seal.
In one prior art approach, sealing material disposed between the faceplate and the backplate is heated using a laser beam. The laser beam is intended to melt the sealing material and thereby provide a seal between faceplate and the backplate. Unfortunately, conventional methods for sealing the faceplate and the backplate together often require the use of a high power laser beam or require exposing the sealing material to the laser beam for an extended period of time. As a result, extremely high temperatures are often generated. Exposing the flat panel display to such high temperatures can deleteriously affect the flat panel display. For example, exposing the flat panel display to such high temperatures can cause unwanted outgassing of contaminants, damage to the glass of the faceplate and/or the backplate, and various other problems.
Thus, a need exists for a method and apparatus for sealing a faceplate to a backplate wherein the method and apparatus does not require subjecting the sealing material to a laser beam for an extended period of time. A further need exists for a method and apparatus for sealing a faceplate to a backplate wherein the method and apparatus does not require subjecting the sealing material to a high power laser beam. Yet another need exists for a method and apparatus for sealing a faceplate to a backplate wherein the method and apparatus reduces the amount of heating of the faceplate and backplate.
The present invention provides a method and apparatus for sealing a faceplate to a backplate wherein the method and apparatus does not require subjecting the sealing material to a laser beam for an extended period of time. The present invention further provides a method and apparatus for sealing a faceplate to a backplate wherein the method and apparatus does not require subjecting the sealing material to a high power laser beam. The present invention also provides a method and apparatus for sealing a faceplate to a backplate wherein the method and apparatus reduces the amount of heating of the faceplate and backplate.
In one embodiment of the present invention, the present invention applies a tuned sealing material between a first surface and a second surface. In this embodiment, the tuned sealing material is comprised of a combination of a filler material and a glass material. Furthermore, in this embodiment, the filler material is tuned to absorb electromagnetic radiation of a selected frequency. Next, in the present embodiment, the tuned sealing material is subjected to the electromagnetic radiation of the selected frequency. As a result of tuning the filler material, the tuned sealing material absorbs the electromagnetic radiation of the selected frequency. After absorbing the electromagnetic radiation of the desired frequency, the tuned sealing material is used to attach the first surface and the second surface.
In another embodiment, the present invention includes the features of the above-described embodiment and further recites that the first surface is subjected to electromagnetic radiation of a second selected frequency. In this embodiment, the first surface absorbs the electromagnetic radiation of the second selected frequency and thereby assists the attaching of the first and second surfaces.
In yet another embodiment, the present invention includes the features of the first above-described embodiment, and further applies a thin film to the first surface. In this embodiment, the thin film is adapted to absorb electromagnetic radiation of a second selected frequency. In this embodiment, the first surface absorbs the electromagnetic radiation of the second selected frequency and thereby assists the attaching of the first and second surfaces.